A cable telephony network allows voice to be transported over the Public Switch Telephone Network (PSTN) or using a Packetized Voice mechanism such as Voice over Internet Protocol (VoIP) for voice to be transported over an Internet Protocol (IP) network.
Cable companies have an installed base of equipment, which is primarily directed to the transport of video not voice and data. To provide voice over their infrastructure, cable companies must adapt their networks to accept voice at a great economical expense. Compounding the problem is that the transport of voice is very bandwidth intensive due to, for example, transport overhead. For example, to transport a 64 kilobit per second voice call, in certain circumstances, may require more than 140 kilobits per second of IP traffic. Also, the Cable companies require a Quality of Service (QoS) enabled network and a high processing capacity gateway to support VoIP telephony.
Current Host Digital Terminal (HDT) based voice over cable telephony architectures do not have the required end to end bandwidth to support traditional voice processing without the potential of producing signal degradation. Also, existing Packet Cable based voice over cable telephony architectures do not have the required end to end bandwidth to support traditional voice processing without the potential of producing high network delays. Additionally, the transport of voice traffic and signaling information lead to bottlenecks within the infrastructure of the cable telephony network.